When I meditate while im fasting I find meditation to be much harder. Its hard for me to have my awerness on the meditation. But if I have eaten light food like fruits/veggies I find it much easier to sit and meditate. It feels like my mind need energy to concentrate.

Maybe this mean that I should not dry/water fast for a whole day and try to add some fruits in the day because my body isn't ready for real fasting?
I can handle the low energy that I get while im fasting, sometimes I train with no energy, it works but meditation is important for me so I wont dismiss it.

GO WITH YOUR INTUITION DAILY WHEN AN 'ISSUE' ARISES,AS IT WILL CONSTANTLY SHIFT - I USED TO FIND IT DIFFICULT TO MEDITATE SOMETIMES WHEN FASTING,THEN FOUND THAT IT WAS ACTUALLY EASIER AT OTHER TIMES! GO WITH THE FLOW CPNAM,LOVE HARA.

When we are fasting on water, and we have lots of waste to eliminate, our body uses much of its effort for this elimination process, this makes it more difficult to meditate because the majority of the body's effort is not in the mental plane, but is more on the physical.
However you may notice that while fasting, your consciousness rises up into a heavenly realm while your body uses its energy to move waste in the physical realm, and therefore meditation is more automatic and less controlled by the self.
The reason Fruit helps is because it loosens the substance that the body uses to eliminate waste, and that substance is mucus. Lemonade sweetened with fresh cane-juice, honey, or sugar also helps in loosening the channels of the body so elimination is less of a burden.